/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.zkas.munqr;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

import com.zkas.munqr.camera.CameraManager;

public final class ViewfinderView extends View {

  private static final int[] SCANNER_ALPHA = {0, 64, 128, 192, 255, 192, 128, 64};
  private static final long ANIMATION_DELAY = 80L;
  private static final int POINT_SIZE = 6;

  private CameraManager cameraManager;
  private final Paint paint;
  private final int maskColor;
  private final int laserColor;
  private int scannerAlpha;
 
  // This constructor is used when the class is built from an XML resource.
  public ViewfinderView(Context context, AttributeSet attrs) {
    super(context, attrs);

    // Initialize these once for performance rather than calling them every time in onDraw().
    paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Resources resources = getResources();
    maskColor = resources.getColor(R.color.viewfinder_mask);
    laserColor = resources.getColor(R.color.viewfinder_laser);
    scannerAlpha = 0;
  }

  public void setCameraManager(CameraManager cameraManager) {
    this.cameraManager = cameraManager;
  }

  @Override
  public void onDraw(Canvas canvas) {
    if (cameraManager == null) {
      return; // not ready yet, early draw before done configuring
    }
    Rect frame = cameraManager.getFramingRect();
    if (frame == null) {
      return;
    }
    int width = canvas.getWidth();
    int height = canvas.getHeight();

    // Draw the exterior (i.e. outside the framing rect) darkened
    paint.setColor(maskColor);
    canvas.drawRect(0, 0, width, frame.top, paint);
    canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
    canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint);
    canvas.drawRect(0, frame.bottom + 1, width, height, paint);

    
    // Draw a red "laser scanner" line through the middle to show decoding is active
    paint.setColor(laserColor);
    paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
    scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
    int middle = frame.height() / 2 + frame.top;
    canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);

    // Request another update at the animation interval, but only repaint the laser line,
    // not the entire viewfinder mask.
    postInvalidateDelayed(ANIMATION_DELAY,
                          frame.left - POINT_SIZE,
                          frame.top - POINT_SIZE,
                          frame.right + POINT_SIZE,
                          frame.bottom + POINT_SIZE);
  }

  public void drawViewfinder() {
    invalidate();
  }

  /**
   * Draw a bitmap with the result points highlighted instead of the live scanning display.
   *
   * @param barcode An image of the decoded barcode.
   */
  public void drawResultBitmap(Bitmap barcode) {
    invalidate();
  }
}
